Apparatus for cementing wells



Aug. 26, 1941. D. SCARAMUCCI APPARATUS FOR CEMENTING WELLS Filed June 29, 1939 Patented Aug. 26, 1941 APPARATUS FOR CEMENTIN G WELLS Domer Scaramucci, Norman, kla., assignor to Oil Equipment Engineering Corporation, Oklahoma City, Okla., a corporation of Oklahoma Application June 29, 1939, Serial No. 281,976

13 Claims.

This invention relates to an improved apparatus for cementing wells, and more particularly to the positioning of a cementing plug in an oil well and to means for facilitating such an operation.

When an oil well is drilled, a casing is placed in the well hole so that there will be a small clearance between the outer side of the casing and the surrounding hole. Very often the hole will pass through strata containing considerable water before the oil bearing levelis reached. In order to prevent such water from passing down the well outside of the casing to the oil bearing strata where it will mix in an objectionable manner with the oil, it is the practice to cement the well hole around the lower end of the casing. The cement extends sufliciently far above the lower end of the casing to prevent the downward passage of water. Owing to the depth of such wells, it has been a rather diflicult problem to determine accurately the position of the cement therein. With the increase in depth of wells from several thousand feet up to fifteen thousand feet, the problem becomes more acute.

The practice hitherto has been to let a sounding weight and line down to the bottom of the well and to provide means for indicating when the cement slurry and the cementing plug, which is used to force it downwardly in the well, have arrived at a certain point. This hasbeen determined either by the tension efi'ect of the .cement and plug as-they pass over a determined "part of the weight line, or by indicating and observing at the surface changes in the character of the well fluid at a certain point in the lower end of the well, and thus determining when the cement slurry has reached that point. The

present invention, however, embodies distinct imviscosity of the drilling mud have made this method of locating the plug quite haphazard. Furthermore, the length of the sounding weight line and the greater speed of pumping the cement into position also impair the accuracy of the method just outlined, depending as it does upon a measurement of the distance from the surface to the plug.

It is the principal object of this invention to provide a novel apparatus for accurately positioning a cementing plug with respect to the bottom or shoe of a well casing.

A further object of the invention is to provide a measuring line-with novel means for signaling the arrival of a cementing plug to the position desired by the operator.

An additional object of the invention resides in the provision of an apparatus which makes it unnecessary to follow the cementing plug with a measuring line, and thus enables the operator to pump the cement down the casing with maximum speed.

Among the specific objects of this invention, are the provision of a novel sounding weight provided with a cutting member and a contractible member, and a novel cementing plug construction for cooperation with the cutting and contractible members.

The preceding and other features and advantages of the invention will be better understood and appreciated from a reading of the following detailed description of a specific embodiment in connection with the accompanying drawing, in which Fig. l is a side elevation, partly in section, of a oil well and a casing therefor, which casing is provided with a shoe and a pair of cementing plugs spaced by a cement body; a measuring line and sounding weight together with means for handling the line are also shown in. operative positions;

Fig. 2 is a partial longitudinal section similar to Fig. 1, but with the cementing plugs and cement in different positions relative to the casing and sounding weight; I

Fig. 3 shows in enlarged, longitudinal section the two cementing plugs and their relation to thesounding weight and well casing;

ing ormeasuring line l2, supported by a guide pulley ll mounted on a casing head and stufling box l6, and a winding and measuring reel l8 for paying out the line l2. A line weight indicator 28 of conventional form is applied to the line l2 between the pulley I4 and reel l8. The weight I8 is shown spaced from the bottom of a well casing 22, provided with an apertured bottom shoe member 24.

In Fig. 1, a cementing plug 26 is similarly threaded on the measuring line l2 above the weight I8 and is spaced below an upper cementing plug 28 by a body 38 of cement slurry. It will be understood by those familiar with this art, that the well bore surrounding the casing 22 contains fiuid, as does also the casing below and above the two cement plugs 26 and 28. The cement body 38 is forced downwardly in the casing 22 by hydraulic pressure on the uppermost plug 28.

In Figs. 3, 4 and 5, the elongated metal sounding weight I8 is shown in detail. The salient features of the weight l8 are a cutting member or head 34 of conical shape, having a base diameter larger than the cross section of the weight l8, and a compressible or contractible member 35, made from a material such as rubber and secured to the lower end of the weight I 8 as a washer which projects outwardly. Reference is made to Fig. 4, which shows in plan view the relation of the four upwardly turned cutting edges 36 which are spaced and extend as elements along the conical face of the head 34. From Figs. 3 and 5, it will be observed that the contractible member 35 is of generally conical shape, and is hollowed out or recessed at 31 in its bottom portion so as to permit contraction at that point. The measuring line I2 is detachably secured by means not shown to the upper end of the weight l8 through the center of the cutting member 34. Longitudinal movement of the contractible member 35, relative to the weight l8, may be prevented by shaping the adjacent portion of said weight so as securely to retain the contractible member.

The cementing plugs 26 and 28 are identical in construction. The details of plug 26 only will now be described with reference to Fig. 3, which shows both plugs in longitudinal section. Plug 26 has a main, cylindrical body portion 38 which is formed from wood or other material of similar characteristics, and is somewhat smaller in diameter than the inside of casing 22. The body portion 38 is provided with a central, longitudinal bore having a flared lower opening defined by a guide sleeve 48, preferably of metal. A rubber washer 42, having the diameter of the well casing 22, is held in place between the flared end of the sleeve 48 and a. thin washer block 43, comprising a part of the plug body portion 38. On the top-side of the plug body 38 an upturned, skirted washer 44 is secured in place by screw means 46, 46, which extend into the body member 38. The sealing functions of the washers 42 and 44 will be apparent from their relation to the casing 22, as seen in Fig. 3. Originally, the upper washer 44 of each cementing plug extends as a diaphragm over the upper end of the plug bore defined by lining 48, and has only a central pin hole for threading the measuring and guiding line l2 when the plugs and weight are assembled thereon. All of the weight l8 except the outwardly projecting, rubber member 35 will slide loosely in the bores of the plugs 26 and 28.

The operation of the novel apparatus which has been described will now be explained. As a preliminary to the cementing of the well which has been illustrated, the regular casing head will be removed and the combined stufiing box and casing head I 6 will be installed as shown in Fig. 1. Before the head I6 is attached to the casing 22, however, the upper cementing plug 28 will be threaded on the weight line l2, which has been passed through the upper end of said head, and the lower cementing plug 26 will also be similarly threaded. After this, the weight [8 will be secured to the free end of the line 12 and lowered into the well casing 22 until it has reached the bottom thereof. It will then be raised a predetermined and measured distance from the bottom or shoe 24 in the manner shown in Fig. 1. The lower plug 26 will then be let down the line below the casing head, the upper plug 28 being releasably retained in any wellknown manner within the casing head l6, which is now attached. A rod 58, which is reciprocable transversely of the head I6, is indicated in Fig. 1 for this purpose. The desired amount of cement slurry will next be pumped into the casing between the plugs 26 and 28 and through an inlet pipe'52 near the bottom of the head l6. When a desired amount of unset cement has been thus pumped, the upper cementing plug 28 will be released so as to engage the top of the cement body, and hydraulic pressure will be applied through another inlet pipe 54 in the casing head l6.

Fluid will be pumped into the casing 22 through the inlet 54 and against the upper plug 28 to force the cement downwardly into the well, and to displace the fluid beneath the lower plug 26, which fluid is free to pass downwardly through the casing shoe 24 and up the outer sides of the casing 22 in the manner illustrated. When the lower plug 26 reaches the vertically stationary weight In, it will be guided into the bore thereof by means of the flared sleeve 48, and the cutting head will be drawn through the diaphragm washer 44 of the plug so as to enlarge the central pin hole through which the line l2 passes. A very definite indication of the passage of the plug 26 over the weight I8 will be obtained when thecontractible member 35 on the end of the weight engages the sleeve 48 of the plug and is contracted thereby in the manner indicated in Figs, 2 and 3. At this time, the line weight indicator 28 at the surface will show a marked increase in tension on the line l2. This indication will be repeated when the upper cement plug 28 passes over the stationary weight ID in its downward journey. The operator will then known accurately the position of the cement body 38 with respect to the casing 22, and can stop the pumping of pressure fluid above the plug 28. The interaction between the lower plug 26 and the weight ID will serve to warn the operator that the cement 38 is nearing its desired position. Until that time, the cement slurry will be forced down the casing with maximum speed, so as to avoid initial setting which would impair its final strength. The rupturing of the diaphragm washer 44 of the lower plug 26 permits the cement to be forced through that plug, out the apertured shoe 24, and up into space between the well bore and the casing 22 to the final sealing position indicated in Fig. 2.

It will be appreciated that the cement which is left in the casing, the shoe 24, and the trangible plugs 26 and 28 will be drilled out after the cement has set.

In Fig. 6, a modification of apparatus is shown,

in which a preliminary signal or indication of plug positions is obtained by means of an upper weight I00, threaded on to the line 12 and secured thereto at a predetermined distance above the weight Ill previously described. It is believed the operation of the apparatus with this modification will be' largely obvious from the previous explanations, the only difference being that the lower plug 26 and upper plug 28 will have their diaphragm washers 44 first cut or ruptured by the upper line weight line I00, and that each will give a definite indication on the instrument as it passes over the weight I00.

With the present procedure, the only measurement which must be taken with the line I! is the distance the weight is to be located above the bottom of the casing. While the distance of the weight from the top of the casing could be measured, considerations of accuracy and simplicity make the other measurement preferable.

The foregoing description of the preferred form of apparatus is illustrative, since it will -be apparent to those familiar with this art, that variations and modifications can be made which will come within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for cementing oil wells comprising, in combination, a measuring line, a weight having a cutting top portion and a contractible bottom portion attached to the end of the line, a plug having a longitudinal bore for receiving the measuring line, said bore being of a diameter which will contract the bottom portion of the weight as it passes therethrough, and a frangible diaphragm attached to an end of the plug over the bore and provided with a small aperture for receiving the measuring line, and adapted to be enlarged by the cutting top portion of the weight as the plug passes thereover.

2. Apparatus for cementing oil wells comprising, in combination, a measuring line, an elongated weight having a cutting head of conical shape and a contractible bottom portion, also of conical shape, attached to the end of the line, a plug having a longitudinal bore receiving the measuring line, said bore being of a diameter which will contract the bottom portion of the weight as it passes therethrough, and a frangible diaphragm attached to an end of the plug over the bore and provided with a small aperture for receiving the measuring line and adapted to be enlarged by the cutting top portion of the weight as the plug passes thereover..

3. Apparatus for cementing oil wells comprising, in combination, a measuring and guiding line, a weight including a conical head with knife edges thereon and an outwardly projecting, contractible bottom portion attached to the end of the line, a plug having a longitudinal bore with a flared lower end for receiving the measuring line and weight, said bore being of a diameter which will contract the bottom portion of the weight as it passes therethrough, and a rubber diaphragm attached to an end of the plug over the bore and provided with a small aperture for receiving the measuring line, and adapted to be enlarged by the cutting top portion oi the weight as the plug passes thereover.

4. Apparatus for cementing oil wells comprising, in combination, a line, an elongated weight having a cutting top portion and an outwardly projecting, contractible bottom portion attached to the end of the line, a cementing plug having a longitudinal bore for receiving loosely the line and weight, said bore being of a diameter which will contract the bottom portion of the weight as it passes therethrough, and a rubber washer for the plug attached as a diaphragm to an end of the plug over the bore and provided with a small aperture for receiving the line and adapted to be enlarged by the cutting top portion of the weight as the plug passes thereover.

5. Apparatus for cementing oil wells which comprises plug means for forcing cementing material downwardly of the well casing and a measuring line having a weight provided with a resilient portion which is adapted to be materially contracted when the plug means comes into engagement with it.

6. Apparatus for cementing oil wells which comprises plug means for forcing cementing ma.- terial downwardly of the well casing, a measuring line having a weight with a resilient portion which is adapted to be contracted when the plug means comes into engagement with it, and means cooperating with the line at the surface for signaling the engagement of the plug and weight.

7. Apparatus for cementing oil wells which comprises plug means for forcing cementing material downwardly of the well casing, and a measuring line having a weight with a resilient portion which is adapted to be contracted when the plug means comes into. engagement with it, said resilient portion being generally conical in shape with its base recessed to facilitate contraction.

8. Apparatus for cementing oil wells which comprises plug means for forcing cementing material downwardly of the well casing, and a measuring line having a weight provided with an attached rubber portion which is adapted to be contracted when the plug means comes into engagement with it.

9. The combination comprising a line and an elongated weight attached to an end of the line so as to hang vertically, said weight having a cutting head on its top end and a contractible, outwardly projecting member adjacent its bottom end.

10. The combination comprising a line and an elongated metal weight attached to an end of the line so as to hang vertically, said weight having a conical cutting head on its top end and a contractible, outwardly projecting rubber mem ber adjacent its bottom end.

11. The combination comprising a line and an elongated metallic weight attached to an end of the line so as to hang vertically, said weight having a contractible, outwardly projecting conical member adjacent its bottom end.

12. The combination comprising a sounding line and an elongated weight attached to an end of the line so as to hang vertically, .said weight including a conical head on its top and upwardly turned knife edges attached to said head.

13. The combination comprising a line and a plurality of elongated weights secured to said line in spaced relation, each of said weights including a cutting head and an outwardly projecting, contractible member. 

